<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>

  <div id="app"></div>
  
  <script src="./lib/react.js"></script>
  <script src="./lib/react_dom.js"></script>
  <script src="./lib/babel.js"></script>
  <script type="text/babel">
    // 1.定义变量
    const message = "Hello World"

    // 2.渲染内容
    const root = ReactDOM.createRoot(document.querySelector("#app"))
    root.render(<h2>{message}</h2>)
  </script>

</body>
</html>